1. Field of the Invention
The invention relates to the field of binary adders or summers.
2. Prior Art
In a typical binary adder a plurality of cells are used, each of which receives a carry-in signal from the preceding cell. The carry signal propagates from one cell to the next. This propagation, particularly for larger binary words, causes the addition to be somewhat slow. In some cases, carry lookahead circuits are used to speed up this process.
Where three digital words are to be summed with prior art circuitry, as will be discussed in conjunction with FIG. 1, two carry signal paths are present causing even a greater time delay.
As will be seen, the present invention provides an adder for adding or summing three binary words with only a single carry signal path.